Both depressive disorders and alcoholism are associated with high societal costs due to increased use of health services, and increased morbidity, including work loss days and limitations in other domains of functioning. Yet relatively little is known about the impact of comorbid alcohol about on the use of services or functional status of depressed patients. One might expect that alcoholism might have an especially strong effect on these outcomes in depressed patients, whose functioning is already compromised. To determine whether comorbid alcoholism is of particular importance in depressed patients, we propose to compare the effects of such comorbidity to the effects of comorbid alcoholism in patients with serious medical conditions. We propose to conduct secondary analyses of existing data from the Medical Outcomes Study to examine the effects of three parameters of drinking (alcohol disorder, problem drinking, and recent consumption) on the use of health services and functional outcomes (i.e., change in functional status over time)for patients who have depressive disorder or a serious chronic medical condition (hypertension, diabetes, or advanced coronary heart disease) but no depression. For patients with depression, we will also estimate the effects of drinking on the clinical course of depression. Because the impact of comorbid alcoholism is determined not only by its consequences, but also by its prevalence, we will also determine the prevalence of alcoholism, problem drinking, and heavy recent consumption for depressed patients and the medically ill, nondepressed samples. Our analyses will use clinically-detailed data base collected on large samples of adult outpatients who had an ongoing relationship with either a general medical provider or a mental health specialist in one of three health care delivery systems in one of three U.S. sites. We propose to use a multi-disciplinary research team with extensive experience with these data. The analyses will use regression models to estimate both the unadjusted associations between comorbid alcohol abuse and use of services and functioning; and the adjusted associations (i.e., controlling for other patient characteristics.)